二氧化铀对CO和CO<SUB>2</SUB>的吸附热力学

二氧化铀对CO和CO₂的吸附热力学

摘要: 采用静态吸附容量法，测定了温度273～303 K、压力0～1 kPa范围内，CO和CO₂在UO₂表面的吸附等温线，研究了CO和CO₂的吸附热力学性质。结果表明，Langmuir方程和Freundlich方程分别是描述CO和CO₂吸附的最优模型方程。CO₂的吸附强度明显高于CO的，实验条件下，CO和CO₂的最大吸附量分别为0.36和1.25 μmol/g。CO的吸附热为26 kJ/mol，表明吸附为物理吸附；CO₂的吸附热随吸附量增加而减小，当吸附量由0.3 μmol/g增至0.8 μmol/g时，吸附热由46 kJ/mol降至37 kJ/mol，表明吸附同时存在化学吸附和物理吸附。

Abstract: Using static volumetric method, adsorption isotherms of CO and CO₂ on UO₂ were measured for temperature range 273-303 K and pressure up to 1 kPa, and corresponding thermodynamic properties were studied. The Langmuir and Freundlich equations are found to describe best the adsorption of CO and CO₂, respectively. The strength of adsorption for CO₂ is much greater than that for CO with maximum adsorption amounts of 0.36 and 1.25 μmol/g respectively in current experimental condition. The heat of adsorption for CO equals to 26 kJ/mol, which indicates the adsorption of CO is physical adsorption. The heat of adsorption for CO₂ decreases from 46 kJ/mol to 37 kJ/mol for increasing adsorption amount from 0.3 μmol/g to 0.8 μmol/g, which indicates both chemical and physical adsorptions of CO₂ take place.